James l



(No Mdel.) l

. J. L. MGQUARRIE.

TELEPHONE CIRCUIT AND APPARATUS. No. 502,466.'

Patented Aug. 1.1893.

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UNTTED STATESN NPATENT OFFICE.

JAMES L. MCQUARRIE, OF BOSTON, MASSACHUSETTS, ASSIGNOR TO THE AMERICANBELL TELEPHONE COMPANY, OF SAME PLACE.

TELEPHONE CIRCUIT AND APPARATUS.

SPECIFICATION forming part of Letters Patent No. 502,466, dated August1, 1893.

Application filed May 25, 1893. Serial No. 475,449. (No model.)

To all whom it may concern: one of said switchboards the said. line ter-Be it known that I, JAMES L. MCQUARRIE, `minates in a clearing outannunciator and residing at Boston, in the county of Suffolk plug, whileat the other switchboard the line and State of Massachusetts, haveinvented extends through the several sections thereof, 5 certainImprovements in Telephone Circuits having looped in at each section aclearing and Apparatus, of which the following is a out spring jack,which constitutes anew feaspecilication. ture in such circuits. Theclearing out This invention relates totelephone central jack performsthe usual functions of a conoiiice or exchange switchboard `circuits andnecting jack upon multiple switchboards, and 6o ro apparatus, andespecially to the trunk lines serves the additional purposes of, first:an which are employed as links between two disautomatic disconnector ofthe trunk line with 5 tant points, or terminals, which may be loasubstation line, and, second, when the trunk cated on separateswitchboards in the same line is connected with a substation line atroom or building, or may be in the telephone one terminal, of visuallyindicating at all the r 5 exchanges of two widely separated towns orother sections of the switchboard the fact that l cit-ies. the line isin use, and also of interposing an PV Owing to the increased use of thetelephone obstacle whereby the operators are prevented and theconsequent multiplication of subfrom inserting a connecting plugtherein. stations connected with exchanges, it has In carrying out myinvention I associate 7o 2o been found desirable and necessary to inanadditional conductor with the trunk line,

crease the number of such central stations, which extends with it and atthe plug termiand as the subscribers of the several central nal thereofhas connected therein normally stations wish to converse with oneanother, through the back contact of an interposed key trunk conductorsare extended between the the minor portion of a main battery which is z5 several exchanges, which thus serve as links grounded at one pole; atthe opposite termibetween the respective switchboards over nal the saidconductor is branched to a norwhich signaling and conversation may becarmally open spring in each clearing ont jack. ried on between thesubstations associated Ialso provide between each of said terminalstherewith. At one or both of the terminals an operators instructioncircuit of any suit- 8o 3o of such trunk lines there are usually someable character. Each clearing out jack conmeans provided to .indicate tothe operator sists preferably of a body of insulating matethere that thesubstations which have been rial supporting an electro magnetandsuitable connected for conversational purposes, have connectingsprings and is provided with a finished, such means being denominatedplug orifice in which there is located a self 35 clearing outannunciators, or visual sigretracting longitudinallymovable circuitconnais, or sometimes such an indication is controller, by means ofwhich, when the looping l veyed by speech from one operator to the orconnecting plug is inserted in said orifice, f other. In all such meansor devices more or the circuit connections are made and the cirless timeis taken up in the notification and cuit controller is operated andlocked, and 9o F `4o frequently an operator is too busy to make theminor portion of said battery or source of the disconnection required,and consequently electricity at the other terminal is closed to a trunkline forming part of a line of comearth through the electro magnets ofall the munication on which a conversation latelyin clearing out jacksat the several switchboard progress has been completed is thought to besections, and line in use indicators are op- 45 still inactiveemployment, and consequently erated. Upon the termination of conversaremains idle and useless, when its employtion between two substationsconnected by ment may be required by other operators at means of such alinking trunk line, the clearother sections of the switchboard. ing outannunciator at the plug terminal end My invention relates to a trunkline which thereof is operated when either of said sub- :oo 5o extendsbetween distant terminals, each terstations ring ott, whereupon theoperator there minal being located upon a switchboard. At A noticing itsfall withdraws the connecting plug and presses the key in the kbatteryline, thereby closing the whole battery current through theelectromagnet of the clearing out jack at the other terminal in whichthe connecting plug of the other substation is inserted, energizing thesame, and operates the locking device of the self retracting circuitcontroller, unlocking the same, whereupon the connecting plug of thesaid substation line is forcibly ejected from the jack, therebyautomatically disconnecting the line, and the plug fallsnto its normalposition upon the operators table; at the same time the line in useindicators of the several clearing out jacks upon the several sectionsof the switchboard are caused to indicate that the line is not in use;all of which I will now proceed to describe. in detail, and to point outin the appended claims.-

In the drawings forming a part of this specification Figures 1 and 2 aresectional Views of my improved clearing out jack, the first in itsunused position and the second with a plug inserted, and Figure 8 is adiagrammatic representation of circuits, illustrating the connection oftwo substations by Vmeans of a trunk lineY extending between Vtwocentral stations, toV which the substations are respectively connected.y

In Figs. 1 and 2, 3 represents the front or face of a switchboard to therear of which the clearing out jacks are attached, or it may represent arubber strip to which a number of other connecting jacks are attached.

4 is a metal thimble to which thejack is directly attached.

The body 5-of the jack, is of hard rubber, and bears'upon 'its outer endan electro magnet 6, which has an armature 9 pivoted at 8. Upon its end,the armature is provided with a lever 7, which extends over its top, theend of which is under the outer end of the lever 10, pivoted at 11.

15 is a chamber hollowed out in the end of the body 5, into whichprojects an arm 12 from the lever 10, the end of which is inclined asshown.

15 is a prolongation .of the lever 10, in the Y form of a dat steelspring. It projects through an opening 17 in the rubber strip 3, and isbent downward to form a shield 16.

19 is a spindle located in the center of the body 5,y one end of whichbears a cone shaped head 14, which projects into the chamberl. Its otherend rests in the thimble 4.

41 is a ring abutment on the spindle and s a spiral spring pressingagainst it and the rear end of the slot 40 cut through the body 5.

18 and 22 are at springs secured to opposite sides of the body 5, theirfree ends extending into the slot 40 and pressing upon the insulatingsection 2O of the spindle 19.

23 is a at spring secured over but insulated from the spring 22; itsfree end resting upon the spindle 19.

In Fig. 2 a connecting plug P2 is inserted in the thimble 4 and jack J.The spindle 19 is trunk line circuit D which extends between" twodistant exchanges X and Y and provided at theforme'r exchange with aclearing out annunciator o2 and a terminal connecting plug P, and at theother exchange with au- `tomatic disconnecting or clearing out jacks Jone on each section of the said switchboard. One side 1 of the circuit Dis branched by wires 27 to the spring 23 of each jack Jat the terminal Yand the other side 2 thereof is branched by wires 29 to the thimbles 4of each jack. A local circuit is formed by wire 43 branching to thesprings 1S of each jack from which branch there extends legs 44 throughthe electromagnets 6 to earth e.

c is a conductor extending parallel with the trunk circuit D providedterminal X with a source of electricity B the circuit being from line tokey 7c, back to contact b wire ci, to ground e, through a minor portionof the battery B; and at the terminal Y it is branched to the spring 22of each jack Jby the Wire 26.

O represents a line extending from sub-l station :c to the switchboardat exchange X, andY C represents a similar line extending fromsubstation y to the switchboard at exchange Y. Each of theselines isprovided with jacks j for each operators section of the switchboard, andwith line aununciators rin a manner well understood.

Ais an instruction circuit provided with operators telephones t at eachexchange, and with such other appliances as is usual.

d represents the operators interconnecting apparatus, of which only theconnecting plugs and looping cords are shown. Y Y j Y To illustratetheoperation of my invention, let us suppose thata call is sent in fromsubstation ,which operates its annunciator o.

The number of the substation Wanted having been ascertained in the usualmanner by the operator, the plug P of the trunk line D is inserted inthe jackj of the line C, and the operator at exchange Y is informedthrough the instruction circuit A of the substation wanted, who theninserts one of the plugs P2 of the loop CZ into the special trunk linejack J upon her switchboard section, and inserts the other plug l?3 intothe jacky' of the substation line wanted, and calls up the subscriberthere,

vswitching out all of the keyboard apparatus and leaving in simply theplugs and cords when the connection has been made. When Ithe operator atexchange Y inserted the plug P2into the jack J, it forced the spindlecircuit l'OO controller 19 inwardly, its cone shaped head 14 strikingthe lever arm 12 pushing it upward against the resiliency of the springl5, (whose shield 16 finds an abutment against the plug) which springsback and locks the spindle, as shown in Fig. 2. A circuit is now closedfrom ground e atexchange X, through a portion of battery B overconductor c, branch 26, throughspindle 19, spring 18, wire 25, to point24, where a portiongoes through the electro magnet 6 of the jack toground at e. The remainder of the current passes by the local wire 43and its branches 25, through the electro magnets of the other jacks J,to ground, and is of sufficient strength to operate their severalarmatures 9, `and thereby elevate the levers l0, and depress the shields16 to cover the orifices or `plug holes of the jacks, thus indicatingthat the line is in use, and also interposing an obstacle to prevent thejack being used. The current is not however strong enough to attract thearmature of the connected jack J against the resiliency of the spring15, and consequently the spindle 19 remains locked. When conversationbetween the substations has terminated, a ringing off signal is sent infrom either or both substations, which operates the clearing outannunciator u2 at exchange X, giving notice to the operator there of thefact, who thereupon withdraws the plug P, and instead of calling theoperator at exchange X to disconnect there, she presses the key k tomake contact with its anvil, thus opening the shunt wire aand includingthe Whole or major part of current of the battery in the line c, whichis of sufficient strength to operate the armature 9 of the connectedjack J, and elevate the lever 10 against the force of the spring 15, andthereby pull the arm 12 from the head of the spindle 19 and unlock it;the spring s on the spindle is thus brought into action, and forciblypropels the spindle and the plug P2 outward until the head .14 isstopped by its abutment, `but the plug is, ejected from the jackentirely and the 1in@ U is disconnected, the plug falling to its placeupon the table; at the same time the springs 18 and 22 resume theirplaces upon the insulation 20, and all current is cut olf from batteryB. consequently the shields of the sevn eral jacks J move to uncover thejack holes,

and thus indicate that the line is not in use.

Having now fully described my invention, I claim- 1. In a trunk lineextending between two telephone switchboards, the combination of acircuit provided at one terminal with a elearing out annunciator and aconnecting plug, and at its other terminal with one or more springjacks, each having a movable circuit controller in its plug orifice, andan electro magnetic locking and tripping device; with an associatednormally open circuit provided `with a source of electricity; and akeyor circuit switch at one terminal; whereby the said source ofelectricity is included in said circuit when either of said spring jacksare looped to a substation line, for the purpose set forth.

2. In a trunk line extending between two telephone switch boards, thecombination of a metallic circuit provided at one terminal with aclearing out annunciator and a connecting plug and at its other terminalwith a spring jack Vhaving a movable circuit controller in its plugorifice and an electro magnetic locking and tripping device; with anassociated circuit grounded through a circuit switch and a source ofelectricity at one end and connected by a normally open branch to thesaid spring jack; whereby when a substation line is looped to saidspringjack its connecting plug may be automatically disconnected as setforth.

3. In a trunk line extending between two telephone switch boards, thecombination of a metallic circuit provided at one terminal with aclearing out annunciator and a connecting plug, and at its otherterminal with one or more spring jacks each having a movable circuitcontroller in its plug orifice and an electro magnetic line-in-useindicating device; with an associated circuit grounded through a sourceof electricity at one end and connected by normally open branches to thesaid spring jacks; whereby when a substation line is looped to one ofsaid spring jacks, the said circuit controller closes the said source ofelectricity to ground and operates the said line-inuse indicatingdevices, as set forth.

4. The combination with a trunk line extending between two telephoneswitchboards, consisting of a metallic conversation and signalingcircuit, provided at one terminal with a clearing out annunciator and aconnecting plug, and at its other terminal with one or morespriugjaclrs, each having a longitudi- 4nally movable circuit controllerin its plug orifice, and provided with electro magnetic locking,tripping, and line-in-use indicating devices; with an associated circuitgrounded through a circuit switch and a minor portion of a source ofelectricity at one end, and connected by normally open branches to thesaid springjacks: whereby when a substation line is looped atone of thesaid springjacks,the said circuit controller closes the said minorsource of electricity to ground and operates the said line-in-useindicating device; and whereby when the said circuit switch is operatedto include the major portion of the said source of electricity, the saidsubstation line is disconnected and the said line-in-use indicators arerestored to their normal condition, as set forth.

5. In a trunk line, extending between two telephone switch boards, thecombination of a metallic circuit provided at one terminal with aclearing out annunciator anda connecting plug, and at its other terminalwith one or more springjacks, each having a mov- IOO IIO

cuit switch with the said brauch inclndinD the source of electricity.

In testimony whereof I havesigned my name to this specification, in thepresence of two subscribing Witnesses, this 16th day of 15 May, 1893.

JAMES L. MCQUARRIE. Witnesses:

GEO. WILLIS PIERCE, JOSEPH A. GATELY.

